Electrical coil unit



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DAVID STONE, OF NEW ROCHELLE, NEW Y MFG. CO., OF MILWAUKEE, WISCONS ELECTIltIcAL COIL UNIT.

Application med Marchas, 1922.4

To all whom z't may concern.'

Be it known-that I, DAVID STONE, a citivzen of the United States, residing at New Rochelle, in' the countyfof W'estchester and State of New York, have invented new and useful Improvements in Electrical Coil Units, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

ThisA .invention relates to electrical coil units and more particularly to units comprising a resistance or other conductive element associated with a suitable support.

It has heretofore been customary in many instances to construct, such units by coiling a resistance wire or other conductive elementabout an insulating support which may be of circular or other cross section, terminal portions of the 'element being electrically connected with a pair of' terminal equivalent devices also carried by port and the resistance or other value of the the number of' turns, loops or the like of the conductor located between the adjacent vterminal bands.

owever, whe-re thesize and shape of the base are such that the length of the individual turns or loops constitutes relativelyl a high percentage of the entire length of the conductor required, l experienced in securing exactly the desired resistance -or other value of the conductor where the permissible deviation is less than the supelectrical the value of a single loop or turn, and the present invention has among its objects that of obviating such' difficulty.

Another object is that of providing for sired degree ofaccuracy. l l Another object is that of cheapening, expediting and generally facilitating the conbands or conductor being determined byA great difficulty has been v -cent ofits fixing the electrical length of a coiled or FFICE.

ORK, ASSIGNOR TO THE CTLER-HAMMER IN, A CORPORATION 'OF WISCONSIN.

Serial No. 546,923.

after appear.

In the accompanying drawing wherein are illustrated certain of the embodiments which the invent-ion mayassumein practice,

Flgure l is a side elevational view illustrating a proposed construction;

Fig. 2 is a vertical sectional view of the same; While,

Fig. 3 is a detail view slightly modified construction. I.

eferring to Fig. 1 of the drawing, the same illustrates a support 5 comprising a base of porcelain or other insulating material and having conductive bands 6 and 7 encircling the same, said bands being provided with outwardly bent flattened portions 8 drilled to receive terminal screws 9 or the like and alsohavinga conventional form illustrating a of' means `indicated generally at4 10 forA clamping the same about 'the support 5.

conductor 11 is coiled about the support and connected with all or certain of' the bands 6 and whereby the latter provide both for securement of the cor..- ductor about the base yand also for terminal connection of' said conductor.

The lengths of adjacent bands being assumed to comprise but a small number of turns about the 'base as illustrated, it is obvious that the length of each turn constitutes a relatively high percentage of such total length. That is to say, assuming an individual section of the conductor to comprise ten turns, a single turn Lthereof would thenrepresent 10 per total ohmic or other electrical "alue, whereby such total electrical value of the section might ordinarily, by changing the number ot turns, be varied only in -increments ofapproximately 10. per cent.

.owever. one or optionally both of the adjacent conductive bandsgare provided at different circumferential yportions thereof with intermediate securing means such as the outstruck lugs l2 whereby either end of the resistor may be secured to and about conductor located between spacing of successive securing any one of said intermediate lugs as desired or necessary in order to afford the proper ohmic or other electricalvalue of the conductor section. By this expedient obviously the electrical value of the section of the resistor may be fixed with an accuracy much greater than that provided -by merely increasing or decreasing the number of complete turns, the limit of accuracy obtainable being only determined by the number of intermediate securing devices carried by the individual bands.

Further it is to be observed that by employing a plurality of individual connections upon each of the bands and staggering such connections of the two bands with reference to one another or further by unequal lugs of adjacent bands, then by connecting the individual terminal portions of the conductor to properly selected lugs of the two bands, a differential selection of the electrical value of the conductor section may be effected.

Assuming employment of an integral conductor for all the sections, such conductor will be terminally connected to a.. suitable or desired portion ofthe terminally located band 6 thence Wound for the necessary number of turns about the support and secured to the adjacent band 7 by looping about that lug or other fastening means of such bands determined by the desired electrical value of thatA section of the conductor, thence the conductor vis again wound for the desired number of turns about the base and is again looped to and about the particular lug of the next band determined by the necessary or desired electrical value of the section, such relation being repeated for the number of sections, and the conductor being finally terminally secured to the terminally located band as illustrated.

While the means for securing the resistor to the circumferentially intermediate portions of the several bands' may comprise any one of the numerous forms, including that illustrated in Figs. 1 and 2 just described, it may in certain instances be found desirable to provide securing means such as that illustrated more particularly in Fig. 3 wherein the lugs 13 arestruck outwardly and upwardly from the outside edges of the individual bands rather than from centril portions of the bands as illustrated in the two earlier figures, and arranged either in opposed pairs or staggered.

'l his latter described construction enables a more accurate determination of the point of contact between the conductor and the band than is possible with the earlier construction and is therefore to be recommended where a special degree of accuracy is reired.

'What l claim as new and desire to secure by Letters Patent is: A

l. An electrical apparatus unit comprising a support and a conductor carried thereby, said support having associated means providing for fixing accurately the electrical length of s-aid conductor.

2. An electrical apparatus unit comprising a base and a conductor coiled thereabout, said base having associated means providing for varying the electrical length of said conductor by increments less than the value of a single turn of the conducto-r.

3. n electrical apparatus unit comprising an insulating support and a conductor arranged in looped relation thereto, said support having associated conductive means providing for fixing the effective electrical length of the conductor with an accuracy greater than that attainable by varying the number of loops of said conductor.

i. A resistance unit comprising an insulating base, a conductor coiled thereabout and conductive means associated with said base to provide for securement of the conductor at any of a plurality of regions located within the extent of a single coil of the conductor.

5. resistance unit comprising an insulating base, a resistor coiled thereabout and a plurality of conductive bands clamped about portions of said base and provided with terminals for securement of the resistor thereto, certain of said terminals being located in such circumferential relation to one another as to provide for fixing the effective ohmic value of the conductor located between adjacent bands within limits Whose difference 1s less than the value of the individual turns of the resistor.

6. A resistance unit comprising an insulating base, a resistor coiled thereabout and a plurality of conductive bands clamped about portions of said base and provided with terminals for securement of theresistor thereto, certain of said terminals being located in such circumferential relation to one another as to provide for fixing the effective ohmic value of the conductor 1ocated between adjacent bands Within limits whose difference is less than the value of the individual turns of the resistor, certain of said terminals comprising pairs of lugs struck up from the material of the band.

ln witness whereof, I have hereunto sub-A scribed my name.

nAvrn STONE. 

